gdkwindow-wayland: Obey Wayland buffer semantics

We can't destroy buffers if they're in-use by the compositor. Well,
technically we can, but that is considered undefined by Wayland and
mutter won't cope with it very well -- it simply kills the client.

To solve this, we need to delay the destroy operation until the
compositor tells us that it's released the buffer. To do this, hold
an extra ref on the cairo surface as long as the surface is in-use
by the compositor.

diff --git a/gdk/wayland/gdkwindow-wayland.c b/gdk/wayland/gdkwindow-wayland.c
index 025b03ba222433c06710c8ea2afa8a6d0c669a8b..41a69988a3a5ca7c80bdc565166ef23f9674647d 100644 (file)
--- a/gdk/wayland/gdkwindow-wayland.c
+++ b/gdk/wayland/gdkwindow-wayland.c
@@ -417,7 +417,11 @@ on_frame_clock_after_paint (GdkFrameClock *clock,
 
   data = cairo_surface_get_user_data (impl->cairo_surface,
                                       &gdk_wayland_cairo_key);
-  data->busy = TRUE;
+  if (!data->busy)
+    {
+      data->busy = TRUE;
+      cairo_surface_reference (impl->cairo_surface);
+    }
 }
 
 static void
@@ -610,7 +614,6 @@ gdk_wayland_cairo_surface_destroy (void *p)
   g_free (data);
 }
 
-
 struct wl_shm_pool *
 _create_shm_pool (struct wl_shm  *shm,
                   int             width,
@@ -667,9 +670,11 @@ static void
 buffer_release_callback (void             *_data,
                          struct wl_buffer *wl_buffer)
 {
-  GdkWaylandCairoSurfaceData *data = _data;
+  cairo_surface_t *surface = _data;
+  GdkWaylandCairoSurfaceData *data = cairo_surface_get_user_data (surface, &gdk_wayland_cairo_key);
 
   data->busy = FALSE;
+  cairo_surface_destroy (surface);
 }
 
 static const struct wl_buffer_listener buffer_listener = {
@@ -702,17 +707,17 @@ gdk_wayland_create_cairo_surface (GdkWaylandDisplay *display,
                                  &data->buf_length,
                                  &data->buf);
 
-  data->buffer = wl_shm_pool_create_buffer (data->pool, 0,
-                                            width*scale, height*scale,
-                                            stride*scale, WL_SHM_FORMAT_ARGB8888);
-  wl_buffer_add_listener (data->buffer, &buffer_listener, data);
-
   surface = cairo_image_surface_create_for_data (data->buf,
                                                  CAIRO_FORMAT_ARGB32,
                                                  width*scale,
                                                  height*scale,
                                                  stride*scale);
 
+  data->buffer = wl_shm_pool_create_buffer (data->pool, 0,
+                                            width*scale, height*scale,
+                                            stride*scale, WL_SHM_FORMAT_ARGB8888);
+  wl_buffer_add_listener (data->buffer, &buffer_listener, surface);
+
   cairo_surface_set_user_data (surface, &gdk_wayland_cairo_key,
                                data, gdk_wayland_cairo_surface_destroy);